Synthesis of Novel Thiazole and Pyrrolothiadiazine Derivatives from Aldehyde Thiosemicarbazones.

Abstract

Ring closure reactions O 0130 Synthesis of Novel Thiazole and Pyrrolothiadiazine Derivatives from Aldehyde Thiosemicarbazones. -Substituted thiosemicabazones (I) react with tetracyanoethylene (II) to form heterocyclic compounds of type (III)-(V). A plausible mechanism for the formation of the products is given. -(GOMAA, M. A.-M.; HASSAN*, A. A.; SHEHATTA, H. S.; Heteroat. Chem. 17 (2006) 4, 261-266; Dep. Chem., Fac. Sci., El-Minia Univ., El-Minia 61519, Egypt; Eng.) -M. Bohle 38-041

Synthesis and Antioxidant Activity of Novel Thiazole and Thiazolidinone Derivatives with Phenolic Fragments

“…The relationship between the ability of thiosemicarbazone to inhibit oxidation and the coplanarity of several conjugated fragments of the molecule is known; in addition, in the case of thiosemicarbazones with a phenolic substituent, the ability to intercept radicals is influenced by the possibility of forming a hydrogen bond between the phenolic OH and the azomethine group. To investigate the influence of these factors on the antioxidant properties of the substances, a conformational analysis can be performed [32][33][34].…”

Formation of 5-alkylidenepyrazol-4(1H)-ones and 3-amino-6-aryl-5-cyano-pyridazine-4-carboxylates from arenealdehyde thiosemicarbazones and unsaturated 1,2-diesters

“…4 Recently we reported that the reaction of various aldehyde 4phenylthiosemicarbazones la-d,g with ethenetetracarbonitrile (TCNE, 2) effected the formation of the heterocyclic systems 3-5 (Scheme 1). 5 Thus, products originating from both incorporation ofTCNE fragments (3,4) and of plain oxidative cyclisation (5) were found. 5 Ph-NH-~-NH-N=CH-Ar + S 1a-d,g esters with primary thioamides,7 and methyl phenylpropiolate and l-acylthiosemicarbazides give triazolothiazinones.…”

“…5 Thus, products originating from both incorporation ofTCNE fragments (3,4) and of plain oxidative cyclisation (5) were found. 5 Ph-NH-~-NH-N=CH-Ar + S 1a-d,g esters with primary thioamides,7 and methyl phenylpropiolate and l-acylthiosemicarbazides give triazolothiazinones. 8 Less attention so far have received the reactions of thiosemicarbazones with acetylenic esters.…”